repeating image horizontally

[irishdoc]

I know this has probably been asked but my brain is frozen and can't seem find what I am looking for. I have set my overall page design to 1000px wide but I would like to have my banner background colors repeat left and right of the center area so when a screen resolution of higher than 1000 they can see the background colors reaching the edge of the screen on both sides. I know it has to be a repeating group of somekind or a group setting just can't seem to find it. Help please.

[Drwyd]

Ctrl + Drag a colour to the pasteboard